hi kirtivas...
im a mech guy workin in IT presently... so thot i cud chip in to help U...
i presume u are into floor production based job (since u say u are a hard core engineer)
1. If u do work with the CAD/CAM/analysis-piping s/w's - then u are one fourth a s/w engineer as per my opinion

. Cos if u are invloved with these u ll definitely be doing R&D work developing macros and models (wherein u ll be programming eg: in CNC machines, extensive projects in ANSYS,CATIA). So u arent an alien to the so called IT-field, if u are a part and parcel of the above.
2. Since u are looking for technical mgmt (literally translates into industrial-production mgmt in our field) i feel u are doing the right thing by choosing technical B Schools. (BITS being one among them. Others being IIT's, NITIE which take in only engineers)
3. If u feel ur TECH-B-Skool needs to be AICTE approved then BITS is out of the way [i dunno if its NAAC accredition is of use for HigherEdu]. But personally i feel approval shud not be an issue, since BITS has a brand value and it ll take necessary measures if it needs to uplift its newly born MBA - ex MMS. eg:Symbiosis institutes dint have them intially. after some years it got one.
4. If u wanto have ur degree from the best, i wud lay emphasis on NITIE. Hope u had gone thru their course framework and contents as well [But u got to slog it with seriously best percentilers in CAT]
Since BITS is pretty new it doesnt have much electives like others and its placements have suffered due to recession.
BITS has MIS, SCM, production-operation in core + ERP, services mgmt,tech mgmt,R&D mgmt,Manufac Strategy electives which ll help Ur production thirst . But whether wud it quench urs, is purely ur say.
5. On the hindside, there are a few positives with BITS too.
* The Course is really,really,really affordable. More or less on the lines of FMS and TISS. Ur ROI will be excellent, iff BITS manage to pull up their socks and work their placements issue.
*It has this engineering brand like IIT's and well known across Asia.There are quite a few work-ex/summers studs from mech field doing mba. [Saw their class of 2010 and previous batch and spoke with the student volunteer for BITS-MBA]
*The MMS by BITS is a well known course. So the MBA [shorter version of MMS] from BITS is bound to take shape in the coming years definitely.
I hope the above gist of points helps u

.
Will meet U @ BITS GD-PI session

ATB !!!